JP2008083129A - Cleaning method of shaft for developing roller - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cleaning method of metal parts, which is capable of cleaning the metal parts represented by a shaft for a developing roller, without using a cleaning tank. <P>SOLUTION: In the cleaning method of the shaft for the developing roller, the shaft is cleaned by irradiating the surface of the shaft for the developing roller used for an electrophotographic image forming apparatus with a laser. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a developing roller shaft cleaning method for cleaning the surface of a shaft constituting a developing roller used in an electrophotographic image forming apparatus with a laser.

  Some electrophotographic image forming apparatuses such as printers, copiers, facsimiles, and the like use a developing device typified by a developing cartridge that can be freely attached and detached, such as those that form an image on a developing roller via toner. . In the image forming method using the developing roller, the developing roller in the developing device is driven to rotate, and the toner on the developing roller is supplied to the electrostatic latent image formed on the photosensitive drum to form a visible image. An image is formed by transferring and fixing on a transfer sheet.

  The developing roller is manufactured through various processes including resin layer formation on a shaft having conductivity such as metal. In particular, the surface of the shaft on which the resin layer is formed is required to have a processing accuracy with no contamination. Is. Accordingly, the production process of the developing roller includes a cleaning process of the shaft surface. In the conventional technique, a cleaning method in which the shaft is immersed in a tank filled with a cleaning liquid (hereinafter also referred to as a cleaning tank) is mainly used for cleaning. It was taken to.

  Incidentally, there is a laser removal method as one of the techniques for removing deposits such as resin attached to the surface of a metal part. As a technique for removing a resin from the surface of a metal part using a laser, for example, there is a technique for removing a photosensitive layer at the end of a photosensitive drum having a laminated photosensitive layer using a carbon dioxide gas laser (see, for example, Patent Document 1). In addition, by irradiating the surface of a metal roller with a heat resistant synthetic resin film coated on a metal cylinder surface with excellent thermal conductivity with a laser beam using infrared rays, the synthetic resin film can be removed cleanly from the surface of the metal roller. There is also a technique (see, for example, Patent Document 2). Further, there is a technique related to mold cleaning of a semiconductor manufacturing sealing mold or the like in which a mold having adhered residues is irradiated with a pulsed laser beam so that the residue at the incident position can be peeled off from the mold (for example, patent document) 3).

Furthermore, there is also a technique for performing processing on the surface of the metal part by irradiating the surface of the metal part (see, for example, Patent Document 4). There is technology to do.
JP-A-9-269603 Japanese Patent Laid-Open No. 2000-356717 JP 2004-230750 A JP-A-8-328374

  However, what is disclosed in the above-mentioned patent documents relates to the removal of the resin adhering to the surface of the photosensitive member, the metal roller, or the mold surface with a laser, or the processing of the surface of the component with a laser. It did not suggest cleaning the surface.

  In addition, the cleaning method using the cleaning tank described above is performed by immersing metal parts in an aqueous / solvent-based cleaning medium filled in the cleaning tank, which improves the cleaning performance of the parts surface. There were some obstacles above. First, in the cleaning tank, the removed dirt is likely to float from the component surface, and the removed dirt may adhere to the component surface again. In addition, it is difficult to completely remove detergent components such as surfactants used for cleaning from the surface of the component. If the detergent remains on the surface of the developing roller shaft, the adhesion of the resin layer and the image forming ability will be reduced. Had an influence.

  As described above, the cleaning method using the cleaning tank has a limit in improving the cleaning performance, and a new cleaning technique for expressing high cleaning performance without using the cleaning tank has been demanded. SUMMARY OF THE INVENTION An object of the present invention is to provide a metal parts cleaning method capable of removing dirt on the surface of a part without using a cleaning tank when cleaning metal parts such as a shaft for a developing roller. It is.

It has been confirmed that the problems of the present invention are solved by the configuration described below. That is,
According to the first aspect of the present invention, “developing the developing roller shaft is characterized by irradiating the surface of the developing roller shaft used in the electrophotographic image forming apparatus with a laser to clean the shaft. Method. ].

  According to a second aspect of the present invention, there is provided the cleaning method for a developing roller shaft according to the first aspect, wherein the laser is a pulse laser having an oscillation wavelength of 1047 nm to 1342 nm. ].

  According to a third aspect of the present invention, “the developing roller shaft is made of a metal material having a reflectance of 40% to 95% with respect to the pulse laser. Cleaning method for developing roller shaft. ].

  According to a fourth aspect of the present invention, there is provided the cleaning method for a developing roller shaft according to the second or third aspect, wherein the pulse laser is a YAG laser having an oscillation wavelength of 1064 nm. ].

  In the present invention, the surface of the metal part represented by the developing roller shaft is irradiated with a laser so that the dirt on the surface of the metal part can be removed. In other words, by irradiating a metal part with a laser to generate heat, the dirt on the surface of the metal part is burned or gasified by the heat to remove it from the part surface, thereby making it possible to remove the dirt from the part surface. . Therefore, according to the present invention, the surface of the metal part can be cleaned without using the cleaning tank, and higher cleaning performance can be obtained than when the cleaning tank is used. As a result, since the resin layer is formed on the shaft surface that is not soiled in the shaft for the developing roller, it is possible to reliably provide a developing roller that can stably form a toner image without image defects. It was.

  In addition, according to the present invention, a metal part having no dirt on the surface can be obtained without using a cleaning tank, so that the earth has a more compact and simple structure than the conventional one and energy and resource consumption is reduced. We made it possible to provide environmentally friendly cleaning technology.

  The present invention cleans the surface of a metal part typified by a shaft for a developing roller used in an electrophotographic image forming apparatus using a laser. That is, the present invention removes dirt from the surface of a component by irradiating a laser on the surface of the metal component to cause the metal component to generate heat, and the heat adhered to the surface of the component burns or evaporates.

  As described above, the cleaning method using a cleaning tank in which metal parts are immersed for cleaning cannot sufficiently eliminate dirt floating in the cleaning tank and adhesion of residual detergent to the surface of the metal parts. In other words, in the cleaning method using the cleaning tank, it is difficult to completely remove the dirt, because the surfactant is easily reattached and the surfactant used as a detergent is oriented on the surface of the component. . Therefore, it is difficult for the developing roller made of the shaft cleaned in the cleaning tank to perform stable image formation without image defects due to these effects.

  For example, if a highly polar detergent remains on the shaft surface, the electrical stability of the detergent adhering portion is impaired and a partial leak phenomenon occurs. As a result, the roller surface corresponding to the detergent adhering portion is hard to accumulate electric charge, and the toner cannot be sufficiently charged, and an image defect called white spot is generated. In addition, when a weakly polar detergent remains or when dirt adheres, adhesion of the resin layer is impaired because these deposits exist between the shaft surface and the resin layer. As a result, the resin layer was peeled off from the shaft surface, the charge was excessively accumulated in the peeled resin layer, the toner was not sufficiently supplied to the image carrier, and image defects such as density reduction were generated.

  In view of the above circumstances, the present invention enables cleaning of the surface of a metal part by irradiating the surface of the metal part with a laser and burning or gasifying the deposit on the surface of the part. As a result, in the present invention, the surface of the metal part can be cleaned without using the cleaning tank, so that the problem caused by the redeposition of dirt and the adhesion of the detergent caused by the method using the cleaning tank does not occur, and the shaft is clean. It became possible to apply a resin layer to the film.

  Although the removal technique using a laser is also disclosed in the above-mentioned Patent Document 3 and the like, these are techniques for partially removing unnecessary portions of the resin layer with a laser after forming the resin layer on the surface of the metal part. There is no description or suggestion that a laser is used to clean the surface of a metal part before layer formation. On the other hand, the present invention is to remove the dirt on the surface of the component by irradiating the surface of the metal part with a laser to heat the metal part and burning or gasifying the dirt on the surface of the metal part with the heat. The removal mechanism is different from the technology. As described above, the present invention is based on the idea that metal parts are heated by a laser, and the dirt adhering to the surface is burned, gasified and removed by the heat. Hereinafter, the present invention will be described in detail.

  In the present invention, the surface of the component is cleaned by irradiating the surface of the metal component with a laser. Here, the laser is a light source having a uniform direction, phase, and wavelength, which is obtained by amplifying light like an electrical signal by stimulated emission. The term laser is an acronym for “LASER; Light Amplification by Stimulated Emission of Radiation”. The above English sentence is translated into Japanese meaning “amplification of light by stimulated emission of radiation”.

  The laser is composed of so-called monochromatic light composed of a single light source having a wavelength and frequency, and has directivity in which light emitted from the light source travels with little spread. Further, it has characteristics such that good coherence can be obtained by aligning the phases of light, and that light having high energy and high luminance can be obtained when light is collected by a lens or the like.

  Lasers are classified into oscillation types, which can be broadly divided into continuous wave lasers that oscillate continuously and pulse lasers that oscillate intermittently in the form of a single pulse or a series of pulse trains. Preferably used.

  Further, when lasers are classified based on laser media, they are classified into solid lasers, semiconductor lasers, liquid lasers, and gas lasers, and when classified according to oscillation wavelengths, they are classified into infrared lasers and ultraviolet lasers. A solid-state laser is a laser medium in which active atoms and active molecules are uniformly deposited on a base material such as an amorphous material or a crystal. In addition, the gas laser uses a gas active atom, an active molecule, or a mixed gas containing the gas as a laser medium.

Examples of the laser that can be used in the present invention classified by the laser medium include a YAG laser, a YVO ₄ laser, a YLF laser, a CO ₂ laser, an excimer laser, and a semiconductor laser. Among these, the YAG laser is particularly preferable because a high-power laser can be obtained and versatility is wide so that an optical fiber can be used as a transmission medium.

  First, a YAG laser that is a typical example of a laser that can be used in the present invention will be described. YAG lasers are classified as so-called solid lasers whose laser medium is a solid such as glass (amorphous) or crystals, and the lasers formed are classified as infrared lasers.

The YAG laser uses a YAG crystal (yttrium, aluminum, garnet; Y ₃ Al ₅ O ₁₂ crystal) doped with neodymium (Nd) in the laser medium. By irradiating the YAG crystal with strong light such as a flash lamp or a laser diode, the YAG crystal is excited to form a laser having an oscillation wavelength of 1064 nm.

  YAG lasers can be obtained from both oscillation modes of continuous oscillation and pulse oscillation. In particular, lasers with high peak output can be obtained in pulse oscillation, and an optical fiber can be used for laser transmission. It can be used for various processing operations such as cutting and welding. Since the metal itself can be effectively heated by the wavelength of the YAG laser, it is presumed that dirt can be easily removed.

Similarly to the YAG laser, there is a YVO ₄ laser that uses a laser medium having a structure in which a crystal surface is doped with neodymium. The YVO ₄ laser is formed by using a laser medium in which neodymium (Nd) is doped into a yttrium orthovanadate crystal. As with the YAG laser, when the crystal is irradiated with light such as a flash lamp or a laser diode, an infrared laser having an oscillation wavelength of 1064 nm is formed in an excited state. The YVO ₄ laser can obtain a higher output laser than the YAG laser, but has a shorter crystal excitation life than the YAG laser.

The CO ₂ laser is a gas laser that uses carbon dioxide as a laser medium, and forms an infrared laser having an oscillation wavelength of 10.6 μm. The CO ₂ laser has characteristics such as continuous oscillation (CW) that always emits light and pulse oscillation (P) that emits light instantaneously and has high oscillation efficiency. Used in technology.

  An excimer laser is a laser that is formed by using a hetero excimer such as a rare gas excimer, rare gas halide, or mercury halide as a laser medium. It is a gas laser having an oscillation wavelength of 150 to 350 nm. It is classified into. Excimer lasers pulse light in the short-wavelength visible, ultraviolet, or vacuum ultraviolet region by discharge in a mixed gas of rare gas and halogen or stimulated emission when an excimer in an excited state caused by electron beam irradiation returns to the ground state. Oscillates. For example, when the laser medium is KrF, the laser with an oscillation wavelength of 248 nm, when XeCl is used, the laser with an oscillation wavelength of 308 nm, and in the case of ArF, the laser with an oscillation wavelength of 193 nm has a pulse width of several ns. It is obtained at a high repetition frequency with a head output of MW or higher. As described above, the excimer laser is characterized in that it can extract ultraviolet light having high energy. An excimer is a dimer formed by combining an atom or molecule in an excited state and an atom or molecule in a ground state, and a compound composed of two different types of atoms or molecules is called a heteroexcimer. .

  A semiconductor laser is formed of a laser medium having a diode structure using a semiconductor called a laser diode. Laser oscillation is performed by applying a current, and light in the visible region to the near infrared region having an oscillation wavelength of 600 to 1600 nm is generated. It is obtained. Semiconductor lasers use gallium / arsenic (Ga / As) crystals, gallium / aluminum / arsenic (Ga / Al / As) crystals, and indium / gallium / arsenic / phosphorus (In / Ga / As / P) crystals as laser media. It can be obtained from any oscillation type, continuous oscillation or pulse oscillation. In addition, semiconductor lasers are widely used in optical fiber communications, CD players, laser printers, laser scanners, and the like, and are currently the laser oscillator elements with the highest production volume.

  Next, cleaning of the shaft using a pulse laser will be described using a specific embodiment. In addition, this invention is not limited to the washing | cleaning form of the shaft for developing rollers shown below.

  FIG. 1 is a schematic view of a shaft cleaning device that can be used in the developing roller shaft cleaning method according to the first embodiment of the present invention. A fundamental wave (wavelength: 1064 nm) of the Nd: YAG laser is emitted from the laser light source 1, for example, a pulsed Nd: YAG laser oscillator. The laser beam is transmitted to the housing 9 through the optical fiber 2. As described above, the YAG laser can use an optical fiber for laser transmission. The housing 9 incorporates a beam shaping optical system 3, a mask 4 having a through hole 4a, a condenser lens 5, a lens moving mechanism 6, a mirror 7 and a mirror rotating mechanism 8, and a window 10 is provided on a side surface. .

  The laser beam transmitted to the housing 9 by the optical fiber 2 enters the beam shaping optical system 3. The beam shaping optical system 3 includes a plurality of optical components including a lens, corrects the laser beam to an appropriate beam size, and emits it as parallel light.

  The laser beam emitted from the beam shaping optical system 3 is shaped into a square or hexagonal cross section, for example, with a mask 4 having a square or hexagonal through hole 4a.

  The laser beam emitted from the mask 4 enters the condenser lens 5. The condenser lens 5 forms an image of the through hole 4a of the mask 4 on the beam irradiation surface. The condenser lens 5 is held by the lens moving mechanism 6. The lens moving mechanism 6 can move the condenser lens 5 in the optical axis direction of the laser beam. The laser beam emitted from the condenser lens 5 is reflected by the mirror 7, passes through the window 10 made of, for example, flat quartz glass, and enters the surface of the shaft 13.

  The mirror rotating mechanism 8 can rotate the mirror 7 and change the incident position of the laser beam incident on the surface of the shaft 13. The mirror rotating mechanism 8 can make the emission direction of the laser beam emitted from the window 10 of the housing 9 perpendicular to the window 10. Further, the laser beam is emitted from the direction perpendicular to the window 10 to both sides along the length direction (left-right direction in FIG. 1) and the width direction (front-back direction of the paper surface in FIG. 1) of the housing 9. , At least 40 degrees or more can be changed. The housing drive system 11 can move the housing 9 along the shaft 13 at a desired speed to change the incident position of the laser beam. The control device 12 controls the movement of the condenser lens 5 by the lens moving mechanism 6, the rotation of the mirror 7 by the mirror rotating mechanism 8, and the movement of the housing 9 by the housing driving system 11. On the surface of the shaft 13, for example, organic compound-based stains 14 such as fats and oils adhere to the surface of the shaft 13. The laser beam is incident on the surface of the shaft 13.

The laser beam shaped into a quadrangular or hexagonal shape by the through-hole 4a has an area of, for example, about 5 mm ² on the dirt 14. When a laser beam, for example, a fundamental wave of an Nd: YAG laser is incident on the residue 14, the dirt 14 transmits most of the fundamental wave of the Nd: YAG laser, and the shaft 13 reflects this by 40 to 90%. Due to the lifting phenomenon, the dirt 14 at the position where the laser beam is incident is peeled off and separated from the surface of the shaft 13, and a removed portion 14 a is formed on the dirt 14. The removed portion 14 a is formed as a result of removing the dirt 14 having the same area as the image formation area of the laser beam from the surface of the shaft 13.

  When the pulse laser beam is scanned so that the beam incident position moves on the shaft 13, removal portions 14 a are successively formed at different positions on the shaft 13. Adjustment of the incident position of the beam is performed by movement of the housing 9 by the housing driving system 11 and rotation of the mirror 7 by the mirror rotating mechanism 8.

  If the irradiation position of the laser beam changes, the optical path length of the laser beam from the condenser lens 5 to the beam irradiation position of the shaft 13 also changes, and the through hole 4a does not form an image on the beam irradiation surface. The lens moving mechanism 6 moves the condenser lens 5 in the direction of the optical axis of the laser beam so that the optical path length from the condenser lens 5 to the beam irradiation position is constant, and the through hole 4a is always at the beam incident position. Make an image.

  Some shafts 13 have a taper of, for example, about 6 to 15 ° at their ends. When removing the dirt 14 on the tapered portion, the mirror 7 is rotated by the mirror rotating mechanism 8 so that the incident angle is as small as possible compared to the incident angle of the laser beam incident on the other portion of the shaft 13. It is preferable that a laser beam is incident on. This is because when the incident angle of the laser beam incident on the shaft 13 is increased, the beam spot on the beam irradiation surface is increased, and as a result, the fluence of the incident beam is decreased, and the dirt 14 cannot be sufficiently separated and separated. This is because there is a fear. Further, when the laser beam is scanned on the shaft 13 and the incident position of the beam is changed, the housing 9 is moved by the housing driving system 11 while the lens 5 is moved by the lens moving mechanism 6, and the mirror is rotated. The mirror 7 is rotated by the mechanism 8.

  The movement of the housing 9 by the housing driving system 11, the rotation of the mirror 7 by the mirror rotating mechanism 8, and the movement of the condenser lens 5 by the lens moving mechanism 6 are all controlled by the control device 12. The shape of the shaft 13 is input to the control device 12 in advance, and these are controlled so that the through hole 4a forms an image on the shaft 13 according to the position where the beam is incident.

  When the laser beam is irradiated and the dirt 14 is separated and removed from the shaft 13 by using the lifting phenomenon, the surface of the shaft 13 is hardly damaged. Therefore, it is possible to overshoot the laser beam (injecting a plurality of shot pulse laser beams at the same position). The dirt 14 that is difficult to separate in one shot can also be separated and removed by multiple shots. Moreover, all the stains 14 can be easily removed at high speed by performing overshoot while scanning the laser beam.

  In addition, the mask 4 having the rectangular or hexagonal through-hole 4a is used to form a beam spot (image of the through-hole 4a) of the laser beam incident on the shaft 13 in a rectangular or hexagonal shape on the surface of the shaft 13. This is because it is preferable for efficiently removing existing dirt.

  The housing 9 is provided with one window 10 on one surface and on the surface facing the surface. The shaft cleaning device is installed so that they respectively face the shaft 13. By installing in this way, the shaft cleaning device shown in FIG. 1 can clean the surface of the shaft 13 efficiently.

  Since the dirt 14 can be removed more favorably as the intensity distribution in the beam spot of the laser beam on the surface of the shaft 13 becomes more uniform, a homogenizer that makes the intensity of the beam on the beam irradiation surface closer to uniform is a beam shaping optical system. 3 can also be joined.

  The use of the optical fiber 2 to transmit the beam from the laser light source 1 to the housing 9 is suitable for introducing the beam into the housing 9 that is displaced in a two-dimensional direction by the housing driving system 11. Because. The optical fiber 2 can ensure optical coupling between the laser light source 1 and the housing 9 even when the housing 9 moves.

  Furthermore, instead of providing the laser light source 1 and the optical fiber 2 separately, a fiber laser having both functions can be used.

  If the interference of the laser beam after passing through the mask 4 is negligible, even if the condensing lens 5 and the lens moving mechanism 6 are removed from the shaft cleaning device shown in FIG. Is possible.

  Next, Fig.2 (a) is the schematic of the shaft cleaning apparatus in 2nd Embodiment. The shaft cleaning device shown in FIG. 2A is different from the shaft cleaning device shown in FIG. 1 except for the condenser lens 5, the lens moving mechanism 6, the mirror 7 and the mirror rotating mechanism 8, and a new housing swing system 15 is provided. It is added. The housing swing system 15 can swing the housing 9 so as to swing the laser beam emission direction in a two-dimensional direction. In the shaft cleaning device shown in FIG. 2A, only one window 10 is provided on one surface of the housing 9 so as to face the housing swinging system 15. A shaft cleaning device is installed so that the window 10 faces the shaft 13 from which the dirt 14 is to be removed. Further, the control device 12 controls the displacement of the housing 9 in the two-dimensional direction by the housing driving system 11 and the swing of the housing 9 by the housing swing system 15. The shaft cleaning device shown in FIG. 2A does not include the condenser lens 5 and the lens displacement mechanism 6 and is therefore preferably used when the interference of the laser beam after passing through the mask 4 can be ignored. .

  Further, a condensing lens 5 that forms an image of the through-hole 4 a on the shaft 13 and a lens displacement mechanism 6 that displaces the condensing lens 5 in the optical axis direction of the laser beam are added between the mask 4 and the window 10. It is also possible. In this case, in addition to the above-described control, the control device 12 always controls the condenser lens 5 by the lens displacement mechanism 6 so that the through-hole 4a forms an image on the shaft 13 even if the incident position of the laser beam changes. Control the displacement.

  Next, FIG. 2B is a schematic view of the mold cleaning apparatus shown in FIG. 2A in which the housing 9 is rocked by the housing rocking system 15. By swinging the housing 9, the beam emission direction can be changed, and the incident angle of the beam on the surface of the shaft 13 can be changed. For example, in the case where the end portion of the shaft 13 is provided at the tapered portion, when the laser beam is emitted toward the tapered portion, the housing 9 is swung to change the beam emitting direction, and the beam is incident on the shaft 13. The pulsed laser beam is scanned so that the position moves. The laser beam can be incident on the taper portion so that the fluctuation of the incident angle is as small as possible compared to the incident angle of the laser beam incident on the other portion of the shaft 13.

  FIG. 3A is a schematic diagram of the shaft cleaning device in which the housing drive system 11, the housing swing system 15, and the control device 12 are removed from the mold cleaning device shown in FIG. In this shaft cleaning device, the housing 9 can be moved or tilted in any direction by a human hand, the laser beam emission direction can be changed, and the beam can be incident on a desired position of the shaft 13. For this reason, the housing drive system 11 that moves the housing 9 in the in-plane direction (two-dimensional direction) of the shaft 13, the housing swing system 15 that rotates the housing 9, and the control device 20 that controls them are excluded. It is. The optical fiber 2 displaces the housing 9 and ensures optical coupling between the laser light source 1 and the housing 9 even when the emission direction of the pulse laser beam emitted from the housing 9 changes. FIG. 3A shows that the shaft 13 is erected and cleaning is performed.

  FIG. 3B is a schematic diagram showing a shaft cleaning device incorporated in the magic hand 20 in the mold cleaning device shown in FIG. 1 excluding the housing drive system 11. The magic hand 20 can be used to carry and install parts to be attached to the shaft 13 and to take out parts that are no longer needed when assembling the shaft. The control device 12 controls the displacement of the condenser lens 5 by the lens moving mechanism 6 and the rotation of the mirror 7 by the mirror rotating mechanism 8 in synchronization with the movement of the magic hand 20 to efficiently clean the surface of the shaft 13. To control.

1 to 3, the Nd: YAG laser oscillator is used, but an Nd: YVO ₄ laser oscillator, a CO ₂ laser oscillator, an excimer laser oscillator, and a semiconductor laser oscillator are used. Is also possible.

  In the present invention, particularly when a metal material having a YAG laser reflectance of 40% or more and 95% or less is cleaned, it is possible to reliably remove organic contaminants such as oils and fats existing on the surface. That is, with a metal material having a reflectance of less than 40% with respect to the YAG laser, there is a concern that the laser irradiation may affect the surface state of the material, and when the reflectance exceeds 95%, contamination will occur even if the laser is irradiated. There is a concern that it will not be possible to remove sufficiently. In the metal material having the reflectance described above, sufficient contamination can be removed without damaging the surface state by irradiating with the YAG laser, so that it is possible to perform a treatment such as coating on the material surface as it is after irradiation.

  The reflectance with respect to the laser can be measured and calculated by a commercially available reflectance measuring device represented by a reflection spectrophotometer. FIG. 6 is a schematic diagram showing an example of reflectance measurement of a metal material irradiated with a YAG laser. In FIG. 6, the surface of the shaft 13 is irradiated with the pulse laser supplied from the laser light source 1 through the Y-type optical fiber 2. In FIG. 6, the pulse laser is irradiated on the shaft surface from the normal direction of the shaft surface. Then, the reflectance reflected on the surface of the metal material is measured and calculated by sending the laser reflected on the surface of the shaft 13 to the reflectance measuring device 30 via the Y-type optical fiber 2. The reflectance measuring device 30 is set so as to collect all the reflected light generated at the laser irradiation point on the shaft 13. Specific examples of the reflectance measuring apparatus include a reflectance measuring system MCPD-5000 (manufactured by Otsuka Electronics Co., Ltd.).

The reflectance represents the ratio of the remaining lasers excluding the amount of laser absorbed on the irradiated surface and used for cleaning when a pulse laser with a specific wavelength (for example, 1064 nm) is irradiated onto the shaft 13. The reflectance is the ratio of the laser absorbed on the irradiated surface, that is, the following relationship is established between the reflectance. That is,
Reflectance (%) = 1-Absorptance (%)
Have the relationship.

  Next, the developing roller manufactured through the developing roller shaft cleaning method according to the present invention will be described. The developing roller manufactured through the cleaning method according to the present invention has a structure in which the resin layer 17 is provided around the conductive shaft 13 cleaned by the present invention. FIG. 4 shows a typical cross-sectional configuration of a developing roller manufactured through the cleaning method according to the present invention. The developing roller manufactured through the cleaning method according to the present invention is not limited to the cross-sectional configuration shown in FIG.

  The developing roller 18 shown in FIG. 4 includes a conductive shaft 13 and a conductive resin layer 17 containing carbon black on the shaft 13. The conductive resin layer 17 (hereinafter also simply referred to as the resin layer 17) is made of a resin and has a structure in which carbon black is dispersed in the resin. As described above, it is presumed that by including carbon black in the resin layer 17, a certain degree of conductivity is imparted to the resin layer 17, and residual charges generated on the roller surface are likely to leak to the conductive shaft 13. The

  The shaft 13 is composed of a conductive member, and specifically, a metal material such as stainless steel such as SUS304, iron, aluminum, nickel, an aluminum alloy, or a nickel alloy is preferable. Also, a conductive resin in which a conductive material such as the above-described metal powder or carbon black is filled in the resin can be used. Any of the above-mentioned conductive members can control the reflectance with respect to a YAG laser having an oscillation wavelength of 1064 nm to 40 to 90%.

  The resin layer 17 constituting the developing roller 18 forms a toner layer on the surface and charges the toner by frictional charging. Further, the resin layer 17 is required to develop a strong adhesive force between the resin layer 17 and the shaft 13.

  An example of a resin that exhibits this performance is, for example, a polyurethane resin obtained by reacting a polyol and an isocyanate. In addition to the polyol and isocyanate, a chain extender may be added as necessary when the polyurethane resin is produced.

  Specific examples of the polyol include polyurethane polyol compounds such as polytetramethylene ether glycol, poly-ε-caprolactone diol, polycarbonate polyol, and polypropylene glycol. Among these, a polycarbonate polyol that forms a polyurethane resin that prevents a decrease in charge amount of the toner during image formation in a high temperature and high humidity environment is preferable. Specifically, aliphatic or alicyclic polycarbonate polyols such as polyhexamethylene carbonate diol are more preferable.

  Specific examples of the isocyanate include 4,4′-diphenylmethane diisocyanate (MDI), cyclohexane diisocyanate, hydrogenated MDI, isophorone diisocyanate, 1,3-xylylene diisocyanate, 2,4-tolylene diisocyanate, 2,6 -Tolylene diisocyanate etc. are mentioned.

  Moreover, it is also possible to use the urethane prepolymer obtained by making it react so that it may have an isocyanate group in the molecular terminal using the said isocyanate, polyol, and also polyamine.

  Examples of the chain extender include ethylene glycol, propylene glycol, 1,4-butanediol, 1,6-hexanediol, ethylenediamine, trimethylenediamine, tetramethylenediamine, hexamethylenediamine, isophoronediamine (IPDA), hydrazine, and the like. Can be mentioned.

  The developing roller 18 can be manufactured by the following procedure. That is, for example, a coating liquid made of a resin containing carbon black or the like is applied around the shaft 13 that has been cleaned by the shaft cleaning method according to the present invention. Form. In addition, a developing roller having a multilayer structure shown in FIG. 4B may be produced by applying another coating liquid in addition to the above-described conductive resin layer containing carbon black, and performing drying and heat treatment. Is possible. The procedure for producing the developing roller will be further described.

  First, a resin layer forming coating solution is prepared by mixing and dissolving a material for forming the resin layer 17 formed around the shaft 13 cleaned by the shaft cleaning method according to the present invention in an organic solvent. For example, a coating solution containing carbon black is prepared. Further, as described above, if necessary, inorganic / organic fine particles can be contained in the resin layer forming solution. In this case, the fine particles are prepared so as to form a dispersed state in the coating solution. . In this way, a coating solution for forming a resin layer is prepared.

  Next, the aforementioned resin layer forming coating solution is applied onto the shaft 13. As the coating method, various methods can be selected according to the viscosity of the coating solution for forming the resin layer. Specific examples of the coating method include a dipping method, a spray method, a roll coating method, and a brush coating method. In the present invention, these coating methods are not limited.

  And after apply | coating the coating liquid for resin layer formation on the shaft 13, drying and heat processing (temperature; 120-200 degreeC, processing time; 20-90 minutes) are performed, and the solvent in the coating solution for resin layer formation is removed. By doing so, the resin layer 17 is formed.

  Further, before and after the formation of the above-described resin layer containing carbon black, for example, by applying another coating solution such as a coating solution containing a silicone copolymer resin, a multilayer as shown in FIG. It is also possible to produce the developing roller 18 having a structure.

  Next, a developing device capable of mounting the above-described developing roller 18 will be described.

  FIG. 5 is a sectional view of the developing device 20 on which the developing roller 18 shown in FIG. 4 can be mounted. The developing device 20 shown in FIG. 5 can perform development using a non-magnetic one-component toner (non-magnetic one-component developer). The developing device 20 is driven to rotate in a counterclockwise direction in the figure by a motor (not shown), and is in contact with or close to an image carrier (not shown) in a state of being incorporated in the image forming apparatus, and the developing roller 18 according to the present invention. And a hopper 23 adjacent to the buffer chamber 22.

  The developing roller 18 includes a conductive shaft 13 that has been cleaned according to the present invention, and a resin layer 17 that is formed on the outer periphery of the shaft 13 using a material such as polyurethane resin.

  In the buffer chamber 22, a blade 24 that is a toner regulating member is disposed in pressure contact with the developing roller 18. The blade 24 regulates the charge amount and adhesion amount of the toner on the developing roller 18. Further, it is possible to further provide an auxiliary blade 25 for assisting the regulation of the toner charge amount and adhesion amount on the developing roller 18 on the downstream side of the blade 24 with respect to the rotation direction of the developing roller 18.

  A supply roller 26 is pressed against the developing roller 18. The supply roller 26 is driven to rotate in the same direction as the developing roller 18 (counterclockwise direction in the drawing) by a motor (not shown). The supply roller 26 has a conductive cylindrical substrate and a foam layer formed of urethane foam or the like on the outer periphery of the substrate.

  The hopper 23 contains toner T which is a one-component developer. The hopper 23 is provided with a rotating body 27 for stirring the toner T. A film-like conveying blade is attached to the rotating body 27, and the toner T is conveyed by the rotation of the rotating body 27 in the direction of the arrow. The toner T conveyed by the conveying blades is supplied to the buffer chamber 22 through a passage 28 provided in a partition wall that separates the hopper 23 and the buffer chamber 22. The shape of the conveying blade is bent while the toner T is conveyed in front of the rotation direction of the blade 27 as the rotating body 27 rotates, and returns to a straight state when the left end of the passage 28 is reached. Thus, the blade T supplies the toner T to the passage 28 by returning the shape straight after passing through the curved state.

  The passage 28 is provided with a valve 281 for closing the passage 28. This valve is a film-like member, one end of which is fixed to the upper side of the right side of the passage 28 of the partition wall. When the toner T is supplied from the hopper 23 to the passage 28, the valve 28 is pushed rightward by the pressing force from the toner T. Can be opened. As a result, the toner T is supplied into the buffer chamber 22.

  In addition, a regulating member 282 is attached to the other end of the valve 281. The regulating member 282 and the supply roller 26 are arranged so as to form a slight gap even when the valve 281 closes the passage 28. The regulating member 282 adjusts so that the amount of toner collected at the bottom of the buffer chamber 22 does not become excessive, so that a large amount of toner T collected from the developing roller 18 to the supply roller 26 does not fall to the bottom of the buffer chamber 22. Adjusted to

  In the developing device 20, the developing roller 18 is rotationally driven in the arrow direction during image formation, and the toner in the buffer chamber 22 is supplied onto the developing roller 18 by the rotation of the supply roller 26. The toner T supplied onto the developing roller 18 is charged and thinned by the blade 24 and the auxiliary blade 25, and then conveyed to a region facing the image carrier to develop the electrostatic latent image on the image carrier. To be served. The toner that has not been used for development returns to the buffer chamber 22 as the developing roller 18 rotates, and is scraped and collected from the developing roller 18 by the supply roller 26.

  The developing bias power supply device 29 provided in the developing device 20 includes a direct current voltage power source that outputs a developing bias voltage and an alternating current power supply device that forms an alternating electric field, although not shown.

  At the time of image formation, the electrostatic latent image carrier (not shown) is uniformly charged by a charging device (not shown), and then a predetermined portion is exposed by an optical head such as a laser. Is attenuated to form an electrostatic latent image.

  In the developing region, the toner that has formed a thin layer on the developing roller 18 flies from the circumferential surface of the developing roller 18 by the action of an electric field formed by the developing bias voltage and the alternating voltage applied from the developing bias power supply device 29. To become a cloud cloud. Then, toner is supplied onto the electrostatic latent image carrier on which the electrostatic latent image is formed, and the electrostatic latent image is developed to form a toner image.

  The thickness of the toner layer formed on the developing roller 18 is, for example, 100 mm / sec for the peripheral speed of the electrostatic latent image carrier, 200 mm / sec for the peripheral speed of the developing roller 18, and the toner regulating member 24 for the developing roller 18. When the pressing force to be pressed is 10 to 100 N / m, a thickness of about 1.5 layers (about 1.5 toner particles) can be formed.

  The developing device on which the developing roller 18 shown in FIG. 4 can be mounted is not limited to that shown in FIG.

Examples of the present invention will be specifically described below with reference to examples, but the present invention is not limited thereto.
(Experiment 1)
Using a laser cleaning apparatus set to the following conditions, the cleaning performance and surface condition of various shafts were evaluated by the following procedure. First, the reflectivity and material (copper, aluminum, stainless steel (SUS303), and nickel) shafts (diameter 16 mm, length 300 mm) shown in Table 1 are prepared, and a laser cleaning device Clean Lasersystem CL120Q (manufactured by Clean Laser). Washing was performed using

  In addition, each shaft before the cleaning treatment is oil and dust, and the fingerprint of the worker, both of which are so dirty that the gloss of the surface is not recognized, the reflectance of each shaft is according to a known method It was obtained by surface treatment.

  The laser that irradiates the surface of the shaft is a pulse laser that performs intermittent irradiation by converting a YAG laser having an oscillation wavelength of 1064 nm to have the following characteristics, and the pulse intensity is as follows: Cleaning performance was measured and evaluated.

Spot diameter: 400 μm
Irradiation spot area: 0.00126 cm ²
Overlap rate: 50%
Pulse intensity (W / cm ² ):
8.3 × 10 ⁶ , 1.3 × 10 ⁷ , 6.4 × 10 ⁷ , 1.7 × 10 ⁸
The overlap rate referred to here is the percentage of the overlap of the laser irradiation spots irradiated intermittently. Further, the pulse intensity refers to the work amount per unit area applied on the shaft by one irradiation of the laser.

  The cleaning process was performed while rotating the shaft so that the laser was irradiated from the normal direction of the shaft surface, the laser was scanned in the axial direction of the shaft, and the cleaning of the entire surface of the shaft was completed in 60 seconds.

  The reflectivity of each shaft is measured and calculated by setting the above-described reflection measurement system MCPD-5000 (manufactured by Otsuka Electronics Co., Ltd.) to count all reflected light generated from the shaft surface. is there. By measuring the reflectivity of the shaft surface after laser irradiation with each pulse intensity, the surface condition variation of the shaft accompanying laser irradiation was evaluated.

The initial reflectivity of various shafts shown in Table 1 to be described later is obtained when the various shafts are irradiated with a YAG laser having an oscillation wavelength of 1064 nm and a pulse intensity of 2.5 × 10 ⁶ W / cm ^2. It is.

  The evaluation of the cleaning performance is a visual evaluation of the surface state of the shaft, and a developing roller is prepared using the shaft that has been cleaned, and this is mounted on an image forming apparatus to evaluate a solid image. is there.

  The developing roller was produced by the following procedure. First, 100 parts by mass of urethane resin “Nipporan 5120 (manufactured by Nippon Polyurethane)”, 30 parts by mass of furnace black and 20 parts by mass of acrylic resin particles (average primary particle size 15 μm) are mixed and dispersed in 400 parts by mass of methyl ethyl ketone (MEK). Thus, a resin layer coating solution is prepared. Next, this resin layer coating solution was applied onto each shaft so that the thickness when dried was 10 μm, and a heat treatment at 130 ° C. was performed to produce developing rollers having different shaft materials.

  The produced developing roller is mounted on a commercially available color laser printer “Magicor 2430DL (manufactured by Konica Minolta Business Technologies, Inc.)”, and a black solid image of A4 size is obtained under a normal temperature and humidity environment (20 ° C., 55% RH). The output was evaluated.

The evaluation contents of the cleaning performance are evaluations of the occurrence of dirt on the shaft and the occurrence of image defects (white spots and density reduction) on the black solid image, as shown below.
<Cleaning performance>
◎: No stain was observed on the shaft, and a good solid image without image defects (white spots and density reduction) was obtained. ○: Although some stain was observed on the shaft, image defects ( A good solid image without white spots and density reduction) was obtained. Δ: Dirt was seen on the shaft, and faint white spots were seen on the solid image, but it was judged that there was no practical problem. X: Dirt on the shaft and image defects (white spots and density reduction) on the solid image appear remarkably, and Table 1 shows the results judged to be practically problematic.

As shown in Table 1, as the pulse intensity in the laser cleaning apparatus increases, the cleaning performance is improved. A shaft made of a material having a low reflectance is better even under a condition where the pulse intensity is low. It was confirmed that cleaning performance was obtained. In particular, when the pulse intensity was set to 1.3 × 10 ⁷ W / cm ² or more, it was confirmed that good cleaning performance was exhibited for any shaft. As a result of the examples, good cleaning performance can be obtained by irradiating the surface of the developing roller shaft with a pulse laser, and good cleaning performance can be obtained without using a cleaning tank as in the prior art. Also confirmed.

  In addition, 3000 sheets were continuously printed after the solid black image was output, and the developing roller after the printing was visually observed. It was confirmed that all the developing rollers were maintained in the state before evaluation. In 3000 prints, an image with a pixel rate of 6% (a thin line image, a full-color human face photo, a solid white image, and a solid black image each ¼ equal) is A4 size. Printed out on paper.

(Experiment 2)
An experiment was conducted except that the sample treated in the same way as in Experiment 1 was used, the irradiation laser was changed to a pulse laser having the following wavelength, and the pulse intensity of the laser was only 6.4 × 10 ⁷ (W / cm ² ). Laser irradiation was performed under the same conditions as in Part 1, and the surface condition and cleaning performance were evaluated. Moreover, as a comparative example, it processed using the washing tank filled with the washing | cleaning liquid which melt | dissolved 10g of commercially available soap for washing | cleaning in 1 liter of water, and evaluated the surface state and washing | cleaning performance.
(1) Nd: YVO ₄ (neodymium doped yttrium orthovanadate) laser with an oscillation wavelength of 1342 nm (2) Nd: YLF laser with an oscillation wavelength of 1047 nm The reflectivity of various shafts shown in Table 2 described later is as described above. As described above, the YAG laser having an oscillation wavelength of 1064 nm and the laser intensity shown in the above (1) and (2) are set to 6.4 × 10 ⁷ W / cm ² and obtained when irradiating various shafts. It is what

Further, as described above, the initial reflectivity of various shafts shown in Table 2 to be described later is irradiating various shafts with a YAG laser having an oscillation wavelength of 1064 nm and a pulse intensity of 2.5 × 10 ⁶ W / cm ^2. It is obtained when you do.

  The results are shown in Table 2.

  As shown in Table 2, it was confirmed that, even in the lasers (1) and (2), good reflectivity and cleaning performance can be obtained with each shaft. On the other hand, what was processed with the washing tank filled with the soap water which is a comparative example was not able to obtain the washing | cleaning performance obtained by what was processed with the pulse laser.

  In addition, 3000 sheets were continuously printed after the solid black image was output, and the developing roller after the printing was visually observed. As a result, the developing roller manufactured through the laser processing of (1) and (2) did not show any change as in Experiment 1, but the developing roller manufactured through the processing in the cleaning tank. It was observed that some of the resin layer ends were slightly peeled off. Note that in the creation of 3000 prints, an image with a pixel rate of 6% (a thin line image, a full-color human face photo, a solid white image, and a solid black image are each divided into quarters) is A4 paper. Output above to create a print.

It is the schematic of the shaft cleaning apparatus by 1st Embodiment. It is the schematic of the shaft cleaning apparatus by 2nd Embodiment. It is the schematic of the shaft cleaning apparatus by 3rd Embodiment. It is a figure which shows an example of the cross-sectional structure of a developing roller. It is sectional drawing of the developing device carrying a developing roller. It is the schematic of the reflectance measurement of the laser in the shaft surface.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Laser light source 2 Optical fiber 3 Beam shaping optical system 4 Mask 4a Through-hole 5 Condensing lens 6 Lens moving mechanism 7 Mirror 8 Mirror rotation mechanism 9 Case 10 Window 11 Case drive system 12 Controller 13 Shaft 14 Dirt 14a (Dirty ) Removal portion 15 Case drive system 16 Magic hand 17 Resin layer 18 Developing roller 20 Developing device 30 Reflectance measuring device

Claims (4)

A developing roller shaft cleaning method, comprising: irradiating a surface of a developing roller shaft used in an electrophotographic image forming apparatus with a laser to clean the shaft. 2. The developing roller shaft cleaning method according to claim 1, wherein the laser is a pulse laser having an oscillation wavelength of 1047 nm to 1342 nm. 3. The developing roller shaft cleaning method according to claim 2, wherein the developing roller shaft is made of a metal material having a reflectance of 40% to 95% with respect to the pulse laser. 4. The developing roller shaft cleaning method according to claim 2, wherein the pulse laser is a YAG laser having an oscillation wavelength of 1064 nm.

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